The first thing to know about Hope Springs is that it is not, despite its published rating, a PG-13 movie. Though no indecent body parts are shown and only a few profanities are used, its subject matter of an older, married couple struggling to overcome their sexual inertia makes for plenty of material that would qualify as R in a sane world. However, with the exception of two scenes that could have gotten their points across without being so explicit, this isn't always a bad thing.
Kay (Meryl Streep) and Arnold (Tommy Lee Jones) have been married for 31 years, but haven't been physically intimate for the last five. Desperate to salvage their marriage, Kay books an intensive therapy retreat in Maine. At first, Arnold agrees to go only on the most grudging terms. When not railing about what a charlatan their therapist (Steve Carell) is, he's complaining about every dime the trip is costing them.
Gradually though, thanks to a staggeringly deft performance by Jones, we see that Arnold's stony waters run very, very deep and that husband and wife both contributed bricks to the wall that now separates them. To break it down, they each have to reach out to their partner in ways that speak most to the other's sense of sexual identity. For Kay, that means showing her husband she wants him; for Arnold, it means showing his wife that he loves her. The general theme coloring all their clumsy, shocking, and occasionally hilarious attempts to reignite the flame is that their tarnished union is a treasure worth saving.
This isn't to say that every bit of "homework" the therapist assigns the couple conforms to biblical principle (he suggests Kay and Arnold attempt a sex act in a public place, though they don't go through with it). But the heart of the movie is about sacrificing pride and risking embarrassment in order serve a spouse in love. The reward is the joy of one of God's greatest gifts in the only context in which mankind can fully and without shame enjoy it-marriage.